DTMF Origins - The Fortuitous Mistake

-

DTMF

DTMF was designed to provide address signaling to CO in PSTN at start of call
Speed user address input (rotary dial was slow)
DTMF originally turned off during conversation part of call
Left on during call because of tip-ring polarity administration issues

DTMF Origins

Created simple, universal user input mechanism for all devices on the PSTN network
end-to-end signaling
standard across all PSTN terminal devices
uPSTN service and application vendors discovered DTMF availability during call in late 70s & began using DTMF for application control

DTMF Usage Today

Virtually all PSTN terminals today have a standard 12-key keypad as a minimum
DTMF for Address signaling is ubiquitous
Universal User Input mechanism - DTMF has become the standard user input mechanism for all types of PSTN voice terminals to interact with services and applications

Popular posts from this blog

History of Labor Day

-
Casting a glance back on Labor Day history is essentially about commemorating and celebrating the American Labor Movement. It is all about knowing the share that the American laborers had in building up the nation with its richness and its many achievements. The Labor Day, usually held on the first Monday in September, inspires this sense of the togetherness that workers need to feel and share in respecting their own contribution to the history of America . Labor Day is an annual recognition of all those dedicated American workers whose achievements, both socially and economically, deserve to be honored. On every Labor Day, Americans pay their tributes to those workers of strength and perseverance whose selfless efforts have added to the growth and prosperity of the American nation. Even after a century-long celebration, there is no one consistent theory about the Labor Day history. The prominent amongst these attributes the Labor Day to one Peter J. McGuire. He is the one who is cr...
Read more

Relationships Ruined by the Internet

-
10 Relationships Ruined by the Internet The wife who found pictures of her husband's wedding to another woman at Facebook Lynn France, a wife who suspected her husband was having an affair, found he was actually married to another woman through a simple Facebook search. All she had to do was type in the name of the woman she believed her husband, John, was seeing. The pair had been married at Disney World , no less, with France's husband dressed as Prince Charming , and his new bride as Sleeping Beauty . There was like an album of 200 pictures there. Their whole wedding. She had grown suspicious when her husband began taking frequent business trips, even leaving the day the couple's newborn son came home from the hospital. Once, she found his passport at home when he was supposed to be in China for business. She once caught her husband with another woman in a hotel so a girlfriend recommended checking the woman's Facebook page, where France...
Read more